Solid casein.



WILLIAM A. HALL, OF BELLOW'S FALLS, VERMONT, ASSIGNOR TO THE LAOTROIDCOMPANY, OF NElV JERSEY.

SOLID CASEIN.

SPECIFICATION forming part of Letters Patent No. 649,690, dated May 15,1900.

Application filed May 13, 1899. Serial No. 716,760. (No specimens.)

To all whom, it may concern;

Be it known that I, WILLiAM A. HALL, a citizen of the United States,residing at Bellows Falls, in the county of XVindham and State ofVermont, have invented or discovered certain new and useful Improvementsin Solid Casein and Process of Producing Same, of which the following isa specification.

This invention or discovery has for its object to provide acomparatively cheap, but reliable, substitute for Vulcanized fiber, hardrubber, or similar substances, and more par ticularly to provide a cheapand efficient material for use as an electrical insulator, my newproduct, unlike themolded products just referred to, being produced by ashrinking or drawing together of the hydrated casein into a homogeneoussolid body or mass of substantially uniform density.

I have discovered that casein (or, in its cruder form, curd of skimmedmilk) has, when properly prepared by hydrating the same, a tendency toshrink or be drawn together as hydrated fibers,- commonly called H 77 Ifcasein or curd be ground when in a wet state into a fine powder orfiocoulent mass, it can be made into blocks, sheets, or boards in thesame manner as rag fiber or wood-pulp. To render the curd capable ofbeing adapted for this purpose, it must be mixed with a large amount ofwater. In other words, the particles of casein or curd must bethoroughly agitated and ground in water, so that the water is beateninto every cell, thus producing a pulp which can be drained in molds oron draining-screens with wire-cloth bottoms similar to those commonlyemployed in the manufacture of hand-made papers. When the hydratedcasein is thus placed in molds or on screens, as above stated, the waterwill be drawn off through the wire-cloth bottoms, and this will requiremore time than is necessary with vegetable fibers. In other words, thehydrated pulp should remain in the molds or on the draining-screensuntil a shrinking action has begun, as I have discovered that theknitting together of the comminuted particles is due to a shrinking or adrawing to gether of the particles, forming a homogeneous mass, althoughno solution of the particles has actually taken place. When the pulp hasbeen thus run into molds or placed on draining-screens, it soon forms atough compact mass, which may be removed and allowed to dry slowly, andin thus drying the shrinking or drawing together of the particles of thehydrated casein causes the water in some way to be expelled from theentire mass, or it is absorbed from the inner portions of the mass bythe outer portions thereof, so that the mass becomes hard. and drythroughout. Vhen thoroughly dried, the compacted casein mass becomeshard, although not brittle, but is, on the contrary, very tough and to acertain extent flexible or elastic or resilient and is adapted for useas a cheap and efficient substitute for pulpboard, vulcanized fiber,vulcanite, celluloid, horn, hard rubber, to. ,and is, as above stated,particularly well adapted for use as an electrical insulator, as caseinor curd is well known to be an excellent insulating substance. Theadvantages of this hardened hydrated casein or caseinoid are itscheapness, non -inflammabi1ity, non absorbtivcness, as also itsresilience and toughness and freedom from deterioration.

The product may be varied to some extent by the precipitant employed incurding the skimmed milk. Rennet as a curding agent gives one result,acid another, and acid salts (such as lead acetate) another, the latterpro ducing a particularly hard product.

If it be desired to render the plates, blocks, or boards formed from thehydrated casein waterproof or non-absorbent, this may easily be done byimmersing them in any suitable sizing mixturesuch as oil or gums, resin,or wax solutions-which will strike in and fill the pores; but evenwithout such treatment they will not dissolve or separate in water. Ifit be desired to make these plates, blocks, or boards proof against analkali, they may be soaked in a weak acid solution or in alum orformaldehyde, or in a combination of any of these substances. Theseplates, blocks, or

boards may be further toughened by immersing them in certain solutions,such as acetate of lead or zinc chlorid, or by boiling in water.

This new product is entirely unlike other casein solids which have beenattempted before. There have been two processes heretofore employed inthe manufacture of casein solids, neither of which have been successfuland neither of which is in commercial use at the present time. In one ofthese processes finely-ground dry casein was subjected to great pressurebetween heated plates, the heat softening or melting the casein to averyslight extent, the pressure causing the particles to adhere together.The objection to this process Was that a heat sufficient to soften thecasein would usually burn it to a slight extent, causing the finishedarticle to be extremely brittle. The articles thus made will always bedark in color. The other process has been simply to make as heavy asolution of casein as possible, using alkali as a solvent, running thisinto molds,and then drying it out. The finished article thus made wassoluble in Water, very brittle, and when perfectly dry would crack ofits own accord. Furthermore,

, it was very difficult to dry out such an article,

as it would soften and run if any artificial heat were applied. Thedrying could usually be only atmospheric. Moreover, this atmosphericdrying required a great length of time, and the product 'could never bemade to dry uniformly, the outside drying first and the center remainingsoft and corky.

My improved hardened casein is in contradistinction to the solid caseinheretofore produced, very tough and to a certain extent flexible andelastic and of substantially the same density throughout instead ofbeing,

like the previous solid caseins, brittle when fully dry and when inthick masses soft inside and hard outside.

- Having thus described my invention or discovery, I claim and desire tosecure by Letters Patent 1. As a new manufacture, plates, boards orblocks of solid casein characterized by toughness, and, to some extent,by flexibility and resilience.

2. As a new manufacture, waterproof or non-absorbent plates, boards, orblocks of solid casein characterized by toughness and, to some extent,by flexibility and resilience.

3. As a new manufacture, hardened or solid hydratedcasein' characterizedby toughness, resilience and substantially-uniform density, and theparticles of which have been compacted by a shrinking together of themass in drying.

4. The herein-described process for producing solid homogeneous casein,consisting in hydrating the casein by grinding and thoroughly agitatingthe same in water so that the water is beaten into every cell thereof,thus forming a thin pulp, and afterward removing the surplus water fromthe casein pulp by draining, and then drying the product and permittingthe same to shrink together.

In testimony whereof I affix my signature in the presence of twoWitnesses.

\VILLIAM A. HALL.

\Vitnesses:

EDWARD SCHOPP, OUsHrNo- ADAMS.

